Combustion chamber



Dec. 6, 1955 A. D. MCDUFFIE 2,

COMBUSTION CHAMBER Filed May 28, 1952 I l l l l Inventor mw Attorneys United S t s Patent*() 6 1 2 254 65 r COMBUSTION CHAMBER Archie D. McDuflie, Berkley, assignor to General Motors Corporation, Detroit, Mich, a corporation; of

Delaware I 1 '7 Application May 28, 1952, Serial No. 290,538

4 Claims-1C1, izs -is'n on commercial The firing chamber is elongated transversely and axially of'the cylinder and has an outlet which is-a's large in cross-sectional area as' anyother'part of the firingchamher. The ignition terminals of a spark plug are disposed in theoutlet sothattheburning will'start in the outlet and will progress acrosstheoutlet'to the clearance space between the piston andthe-head before a large part of the charge is burned "inthe ends ofthe firing chamber remote from theoutlet.

In the drawing:

Figure 1 represents a fragmentary cross-sectional view of an engine, partlythrough the axis of a'cylinder and partly through the axis of one of the valves.

Figure 2 'isa fragmentary :upsidedown plan view of the head of the engine, taken substantially in the plane of} line 2-2 on Figure'l.

The engine 10 comprising the invention includes an engine block 11 having one or more cylinders 12 formed therein. The fblock 11 is provided with cavities 13 for cooling'fluid' for cooling the cylinders '12. The cylinders 12 contain reciprocal piston"1'4 adapted to drive the connecting rods'of a crankshaft through piston pins indicated at-16; The cy1inders'12 of the block 11 have a head -17 adapted to be" bolted or otherwise secured to the block 11 upon a cylinder gasketindicated at 18. The I head 17 hasin'let and exhaust valves Hand 21 respectively adapted to control ports-communicating with the interior of the cylinder '12'and'through which fluid is supplied to and exhausted from the engine through inlet and exhaust passages also formed in thehead 17. One of the inlet passages and one of the inlet ports are indicatedrespectively by the numerals 22 and23. The valves 19 and 21 may be operated in any conventional manner as by being resiliently closed by springs vand opened byroclrer arms and push rodsvactuated byacam shaft driven by the crankshaft of the engine 10; The

inlet passages leadingto the ports 22 controlled by the valves 19 may be supplied with a combustible mixture of hydro-carbon fuel and air'by any'suitable charge forming device for the engine 10. The exhaust passages lead ing from the exhaust ports. controlled by the exhaust valves 21 may beconnectedto any-suitable exhaust system for exhausting the products of combustion from the engine 10.

The piston 14 may be formed in such a way as to provide a plane end wall adjacent the head 17, which is the charge around thetermirials 4 1;

the axes of the valves 19 and21;

uniformly spaced from the adjacent plane surface of the lower wall-260i the head 17'. The space 27 between the walls 24 and 26 of the piston-14 and head 17 respectively provides a minimummechanical clearance for operating the: piston-14. The space 27 also provides a quench space forming a part of the combustion chamber of the engine. The thickn ess of the mechanical clearance or quench -space 27' ordinarily is "of gasket thickness, this beinggenerally in the neighborhood of about .070 of an inch. However, such m'echanical; clearance 'or' quench space may vary""considerably, froma few thousandths of an inch to perhaps'a hundred thousandths of an-inch or more. Thecombustion -chamber'28 of theengine comprises a firingtchamber 29; themechanical clearance or quench space-27- and valveclearance spaces 31 which are-formed part ofthe way around the valves -19 and 21 and which merge with a passage 32 extending acrossthe head 17 to the outlet end of the firing chamber 29; The firing chamber 29 is formed inthe head '17 at one-side of-and relatively close to the valves 19 and '21. However,it is desirable to cool the head '17 and the various passages andengine elem'ents therein. 'Forthis purpose a cooling fluid cavity'35 is formed in the'head 17 in such manner that a part of the cavity extends between the firing chamber 29-and the inlet and exhaust passagescontrolled-by'the-valves Hand 21. t Y 1 a 7 'It is-alsodesirable to construct the head 17- in such 'a way that the'outletend of the firing chamber 29 and the valves 19 and '21 are substantially directly opposed to the open'end of 'the cylinder12. 'In order to insure ease of manufacture and an unrestricted outlet between thefiring chamber 29 and theinterior'of the'cylinder 12 the firing chamberis formed in such a way as to include oppositely disposed semi-cylindrical walls 33 and 34 which project into the head 17 in: parallel relation. It is preferable to connect the edges of the semi-cylindrical walls 33 and 34 by'plane side walls 36 and 37' and that the axes' of the semi-cylindrical end walls 33'and 34 project into the head 17in parallel relation to the axis'of the cylinder'12i The inner end-wall 38 of the firing chamber 29 may be formed of arcuate shape or'in any suitable manner-so-long as it does not contain pockets or other enlargements making the; inner end of the firing-chmber29 larger than the various partsnthereof extendingtoward the firing'ch'ambe'r outlet. The 'engine-10ris-provided with aspark plug 39 which is -securedzin a threaded opening formedinthe head 17 in such a manner'that the ignition terminals '41 of the. spark plugare directly within the outlet by which the firing chamber 29 communicates with the interior of the cylinderll -In the present instance-the outlet end of 41 by anarcuate formed r ecess 42 whieh projectsinto the lower extremity of the side wall 37 of the 'chamber29. Therecess42 isswidetenough andthe terminals 41 are so near being within'the wall 37, that: the wallsof therecess .42. do not materiallyatfectthe initial rapid b'urning'of v The firing chamber 29=extends in length iniparallelrelation to'a line between Also,the spark plug 39 is located approximately atthe mid-point'between the opposite ends of the 'firing chamber 29. his preferred that the axis of the sparkplug 'shouldbedirected obliquely across the: middle of the firing chamber 29 and toward a point immediately below the lower edge/of the sidewall 36 of the firing chamber 29. Hence, the progress of the flame from the terminals 41 will'be directly .across the outlet from the'firing chamber andtoward the middle of the various clearance 's'paces'b'eneath the wall 36 of the head 17. In addition, it is preferred to have the firing chamber also elongated in a direction parallel to the axis of the cylinder 12 so that the terminals 41 of the spark plug 39 are closer to the adjacent edges of the clearance spaces 32 and 27 than to the various parts of the firing chamber 29 which are remote from the outlet by which the firing chamber communicates with the interior of the cylinder 12.

The burning in the combustion chamber 28 will start at the ignition terminals 41 of the. spark. plug 39 and since the ignition terminals are in the enlarged outlet by which the firing chamber 29 communicates with the interior of the cylinder 12 the burning will expand rapidly in the outlet and will progress directly across the outlet to the various narrow spaces where the firing chamber 29 communicates with the clearance spaces 32, 31 and 27. Thereafter the burning will continue toward the more remote parts of the firing chamber 29 and of the clearance spaces 32, 31 and 27. It will be apparent that some parts of the clearance spaces 27 are somewhat remote from the firing chamber 38. However, since the clearance spaces 27 are very shallow and contain very little of the charge in proportion to the area of the piston and the head to which such small portions of the charge are exposed the rate of burning in the clearance spaces 27 will be relatively slow. The clearance spaces 32 and 31 which surround the valves 19 and 21 are relatively not so shallow as the clearance spaces 27 and consequently the burning will be somewhat more rapid in the clearance spaces 32 and 31. However, the clearances spaces 32 and 31 are exposed to a relatively large amount of surface area of the head 17 and the piston 14 and consequently the burning in these spaces is not so rapid as it would be in an unrestricted space. In addition to this, the clearance spaces 32 and 31 communicate directly with the outlet part of the firing chamber 29 which is directly opposite the ignition terminals 41 of the spark plug 39. The edge of the space 32 therefore is nearer the ignition terminals 41 than are the remote parts of the. firing chamber 29. The burning in the clearance spaces 32 and 31,therefore, will start considerably before the final part of the charge is burned in the remote parts of the firing chamber 29 and before the pressure and temperature rise in the charge in the combustion chamber has become excessive. The charge in the clearance spaces 32 and 31 therefore will commence to burn fairly quickly but will burn somewhat slowly across the clearance spaces until the final part of the charge in these clearance spaces is burned.

In the claims:

1. An engine comprising a cylinder having a reciprocal piston therein and inlet and exhaust valves in the head of said cylinder, a firing chamber for said cylinder and projecting into said head at one side of said valves, said firing chamber being formed by spaced semi-cylindrical end walls having the axes thereof disposed in parallel relation to the axis of said cylinder and being tangently connected to one another by parallel and plane side walls, and a spark plug having the ignition terminals thereof projecting into a part of said firing chamber adjacent the outlet of said firing chamber.

2. An engine comprising a cylinder having a reciprocal piston therein and inlet and exhaust valves in the head of said cylinder, a combustion chamber formed in said cylinder and comprising a firing chamber formed in said head at one side of said valves and a minimum mechanical space between the end of said piston and the head of said cylinder and said valves, said combustion chamber also including a valve clearance space extending around each of said valves and between said valves and the outlet leading from said firing chamber, said firing chamber being formed to provide an elongated outlet leading to said cylinder and extending in parallel relation to a line connecting the axes of said valves, said outlet having a cross-sectional area as great as any other part of said firing chamber and communicating with said valve clearance space throughout the length of the elongated outlet from said firing chamber, and a spark plug secured in said head, said spark plug having the ignition terminals thereof projecting into said outlet with the axis of said spark plug directed transversely across said outlet to said firing chamber and toward the middle of the part of said valve clearance space communicating with said firing chamber outlet.

3. An engine comprising a cylinder having a reciprocable piston therein and inlet and exhaust valves in the head of said cylinder and in opposed relation to the end of said piston, a combustion chamber including a firing chamber formed in said head at one side of said valves and a minimum mechanical clearance space formed between the end of said piston and the head of said cylinder and said valves, said firing chamber being elongated in length and height and with the length and height thereof extending in parallel relation to the stems of said valves and with the width thereof extending normally with respect to the stems of said valves, said firing chamber having an elongated outlet having a cross sectional area as great as that of any other inwardly disposed part of said firing chamber and communicating with said minimum mechanical clearance space throughout the length of said elongated outlet, and a spark plug secured in said head, said spark plug having the ignition terminals thereof projecting into said firing chamber adjacent said outlet and with the axis of said spark plug directed transversely across said firing chamber and toward the middle of the opposite wall of said firing chamber, said ignition terminals being positioned in said firing chamber with the spark gap therebetween in position to burn an ignitable charge compressed in said firing chamber directly across said firing chamber and toward said opposite wall thereof and throughout an arc of substantially 180.

4. An engine comprising a cylinder having a reciprocable piston therein and inlet and exhaust valves in the head of said cylinder and in opposed relation to the end of said piston, a combustion chamber including a firing chamber formed in said head at one side of said valves and a minimum mechanical clearance space formed between the end of said piston and the head of said cylinder and said valves, said firing chamber being elongated in parallel relation to the stems of said valves and having an outlet with a cross sectional area as great as that of any other part of said firing chamber and communicating with said minimum mechanical clearance space, and a spark plug secured in said head, said spark plug having the ignition terminals thereof projecting into said firing chamber adjacent said outlet with the axis of said spark plug being directed transversely across said firing chamber and toward the middle of the opposite end of said firing chamber and toward said outlet, said ignition terminals being positioned in said firing chamber with the spark gap therebetween in position to burn an ignitable charge compressed in said firing chamber directly across said firing chamber and toward said opposite end thereof and toward the adjacent edge of said minimum mechanical clearance space and throughout an arc of substantially 180.

References Cited in the file of this patent UNITED STATES PATENTS 1,812,197 Bullington June 30, 1931 1,977,127 Guernsey Oct. 16, 1934 2,012,895 Sidney Aug. 27, 1935 2,041,078 Loeffler May 19, 1936 FOREIGN PATENTS 44,162 France Aug. 20, 1934 (1st addition to Patent 762,680) 431,396 Great Britain July 1, 1935 

